Polymer membranes for continuous analyte sensors

Abstract

Devices and methods are described for providing continuous measurement of an analyte concentration. In some embodiments, the device has a sensing mechanism and a sensing membrane that includes at least one surface-active group-containing polymer and that is located over the sensing mechanism. The sensing membrane may have a bioprotective layer configured to substantially block the effect and/or influence of non-constant noise-causing species.

What is claimed is: 
     
       1. A system for measurement of an analyte concentration, the system comprising:
 an implantable sensor comprising a sensing region configured to continuously produce in vivo sensor data indicative of an analyte concentration in a host, wherein the sensor further comprises a membrane located over the sensing region, wherein the membrane comprises a layer configured to reduce a flux of the analyte therethrough, wherein the layer comprises a material that is a polymer produced by a reaction of an isocyanate; 
 a processor configured to process sensor data; and 
 a user interface configured to display information corresponding to continuous sensor data; 
 wherein the sensor is configured to provide, at analyte concentrations of from 40 mg/dL to 400 mg/dL, a level of accuracy corresponding to a mean absolute relative difference of less than 10% over a sensor session length of from 3 to 7 days, wherein one or more reference measurements used to calculate the mean absolute relative difference are determined by analysis of blood. 
 
     
     
       2. The system of  claim 1 , wherein the membrane comprises a layer configured to reduce a flux of the analyte. 
     
     
       3. The system of  claim 2 , wherein the layer comprises a polymer comprising polyurethane, polyurethane, polyurethaneurea, or a combination thereof. 
     
     
       4. The system of  claim 3 , wherein the polymer further comprises a silicone segment. 
     
     
       5. The system of  claim 2 , wherein the layer comprises a hydrophobic portion and a hydrophilic portion. 
     
     
       6. The system of  claim 1 , wherein the sensor is configured to provide, an analyte concentrations of from 40 mg/dL to 80 mg/dL, a level of accuracy corresponding to a mean absolute relative difference of from 6% to 9.6% over the sensor session length, wherein one or more reference measurements used to calculate the mean absolute relative difference are determined by analysis of blood. 
     
     
       7. The system of  claim 1 , wherein the membrane comprises an enzyme configured to react with the analyte. 
     
     
       8. A system for measurement of an analyte concentration, the system comprising:
 an implantable sensor comprising a sensing region configured to continuously produce in vivo sensor data indicative of an analyte concentration in a host, wherein the sensor further comprises a membrane located over the sensing region, wherein the membrane comprises a layer configured to reduce a flux of the analyte therethrough, wherein the layer comprises a material that is a polymer produced by a reaction of an isocyanate; 
 a processor configured to process sensor data; and 
 a user interface configured to display information corresponding to continuous sensor data; 
 wherein the sensor is configured to provide, at analyte concentrations of from 40 mg/dL to 400 mg/dL, a level of accuracy corresponding to a mean absolute relative difference of from 6.8% to 9.6% over a sensor session length of from 3 to 7 days, wherein one or more reference measurements used to calculate the mean absolute relative difference are determined by analysis of blood. 
 
     
     
       9. The system of  claim 8 , wherein the membrane comprises a layer configured to reduce a flux of the analyte. 
     
     
       10. The system of  claim 9 , wherein the layer comprises a polymer comprising polyurethane, polyurethane, polyurethaneurea, or a combination thereof. 
     
     
       11. The system of  claim 10 , wherein the polymer further comprises a silicone segment. 
     
     
       12. The system of  claim 10 , wherein the layer comprises a hydrophobic portion and a hydrophilic portion. 
     
     
       13. The system of  claim 8 , wherein the sensor is configured to provide, an analyte concentrations of from 40 mg/dL to 80 mg/dL, a level of accuracy corresponding to a mean absolute relative difference of from 6% to 9.6% over the sensor session length, wherein one or more reference measurements used to calculate the mean absolute relative difference are determined by analysis of blood. 
     
     
       14. The system of  claim 8 , wherein the membrane comprises an enzyme configured to react with the analyte.